Facebook PHP SDK-图形错误“;已使用授权码“;页面刷新

我有一个使用facebook登录的网站的个人资料页面。当页面第一次加载时，登录工作正常，一切似乎都正常。然而，当刷新配置文件页面时，我会收到一个错误："图形返回错误：此授权代码已被使用。"通过进行一些研究，我了解到这可能是因为我需要使用当前会话？我在脸书上搜索了开发者，但不知道如何做到这一点。我还研究了其他一些有类似错误消息的页面，但当页面刷新时，似乎没有一个页面覆盖。我使用Javascript SDK进行登录过程，使用PHP SDK进行图形请求和登录后的任何操作。我正在使用的代码以及sql查询如下：

<?php
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
error_reporting(E_ALL);
ini_set("display_errors", 1);
// error reporting is now turned on

require('facebook-sdk-v5/autoload.php');
$fb = new Facebook'Facebook([
    'app_id' => 'app-id-here',
    'app_secret' => 'app-secret-here',
    'default_graph_version' => 'v2.2',
]);
# fb-login-callback
$jsHelper = $fb->getJavaScriptHelper();
// @TODO This is going away soon
$facebookClient = $fb->getClient();
try {
    $accessToken = $jsHelper->getAccessToken($facebookClient);
} catch(Facebook'Exceptions'FacebookResponseException $e) {
    // When Graph returns an error
    echo 'Graph returned an error: ' . $e->getMessage(); /*****This is where the error is caught*****/
} catch(Facebook'Exceptions'FacebookSDKException $e) {
    // When validation fails or other local issues
    echo 'Facebook SDK returned an error: ' . $e->getMessage();
}
if (isset($accessToken)) {
    try {
        // Returns a `Facebook'FacebookResponse` object
        $_SESSION['facebook_access_token'] = (string) $accessToken;
        $response = $fb->get('/me?fields=id,name,email,gender,hometown', $_SESSION['facebook_access_token']);
    } catch(Facebook'Exceptions'FacebookResponseException $e) {
        echo 'Graph returned an error: ' . $e->getMessage();
        exit;
    } catch(Facebook'Exceptions'FacebookSDKException $e) {
        echo 'Facebook SDK returned an error: ' . $e->getMessage();
        exit;
    }
    //Check the database for the user
    //First connect
    require_once 'config.php';
    try {
        $mysqli= new mysqli($host, $username, $password, $dbname); 
        if ($mysqli->connect_error) {
            die('Connect Error (' . $mysqli->connect_errno . ') '
                . $mysqli->connect_error);
         }
     }
     catch (mysqli_sql_exception $e) { 
         throw $e; 
     } 
     $stmt = $mysqli->prepare( "SELECT COUNT(*) FROM users WHERE fbuid = ?");
     $stmt->bind_param("i", $id);
     //Returns a `Facebook'GraphNodes'GraphUser` collection
     $user = $response->getGraphUser();
     $id = $user['id'];
     $stmt->execute();
     $stmt->store_result();
     $stmt->bind_result($count);
     $stmt->fetch();
     //If this is a new user, insert into the users table
     if($count === 0) {
        $stmt->free_result();
        $stmt = $mysqli->prepare("INSERT INTO users (fbuid, name, email, location, profpic, gender, joined)
                                  VALUES ( ?, ?, ?, ?, ?, ?, ?)");
        $stmt->bind_param("issssss", $id, $newName, $newEmail, $newLoc, $newPic, $newGender, $joinDate);
        //Get the date for the joinDate
        $date=getdate(date("U"));
        //Get the required information from the Graph API
        $locationObj = $user['hometown'];
        $joinDate = "$date[month] $date[mday], $date[year]";
        $newName = $user['name'];
        $newEmail = $user['email'];
        $newLoc = $locationObj['name'];
        $newPic = "http://graph.facebook.com/" . $id . "/picture?type=large";
        $newGender = $user['gender'];
        $stmt->execute();
     }
     //Retrieve their info from the users table
     $stmt->free_result();
     $stmt = $mysqli->prepare("SELECT name, email, location, profpic, gender, joined, about FROM users WHERE fbuid = ?");
     $stmt->bind_param("i", $id);
     $stmt->execute();
     $stmt->store_result();
     $stmt->bind_result($name, $email, $location, $profpic, $gender, $joined, $about);
     $stmt->fetch();
} 
else {
    // Unable to read JavaScript SDK cookie
}
?>

我的问题是，如何更改我提供的代码以防止出现此错误。如果必须使用当前会话，我该如何检查和使用它。非常感谢。